1. Field of the Invention
This invention relates to induction heating equipment for bars and more particularly to a work stop and push rod mechanism for use with an induction heating coil to raise the end of a long bar to uniform temperature despite the existence of a residual hot spot on the end of the bar before the heating operation.
2. Prior Art
In forging operations it is common practice to employ an elongated metal bar as forging stock. One end of the bar is heated and after the forging operations are completed the forging is cut off of the end of the bar and the bar is then reheated for a subsequent forging. This practice is termed "heating off the end of the bar". After a completed forging is cut off, a residual hot spot remains at the bar end.
This hot spot doesn't create any problem when the bar is heated in a combustion furnace since the furnace acts to bring the entire bar end up to the same final temperature despite the existence of the hot spot. However, it is not heretofore been practical to use induction heating systems to reheat forging bar ends since these induce energy into the workpiece as a function of the time that the workpiece is in the equipment and if a part orginally has two adjacent sections at substantially different temperatures, after induction heating this temperature differential will still exist. Accordingly, if a forging bar with a residual hot spot is placed into induction heating equipment and the cool end is brought up to forging temperature, the hot spot will be overheated and may even melt.
The present invention is broadly directed toward induction heating equipment designed to bring a forging bar having a residual hot spot on its extreme end up to a uniform forging temperature.